This all plays upon the Fermi paradox and whether or not there is intelligent life looking for other intelligent life for what ever reason. The most likely explanation is that we are alone, the first intelligent life or that higher life forms don't care about us.
Any intelligent Alien race that could receive our message would be light years away. In the time it would take to travel that distance one of our species would likely go extinct. If they are capable of traveling such a distance, they likely use communications far more advanced than radio.